Sports and Exercise Reduces Breast Cancer Rates

Women who actively participate in sports are 25% less likely to get breast cancer, though the benefits are not seen in obese women, and lean women see the lowest breast cancer rates.

The type of activity undertaken, at what time in life and the woman’s body mass index (BMI) will determine how protective the activity is against the disease.

The researchers reviewed the literature and analysed 62 studies looking at the impact of physical activity on breast cancer risk. They then examined the findings to find out how breast cancer risk appeared to be affected by type of activity, intensity of activity, when in life the activity was performed and other factors.

They found the most physically active women were least likely to get breast cancer. All types of activity reduced breast cancer risk but recreational activity reduced the risk more than physical activity undertaken as part of a job or looking after the house. Moderate and vigorous activity had equal benefits.

Women who had undertaken a lot of physical activity throughout their life had the lowest risk of breast cancer, and activity performed after the menopause had a greater effect than that performed earlier in life.

Physical activity reduced breast cancer risk in all women except the obese and had the greatest impact in lean women (BMI < 22kg/m2)

Women who were mothers, had no family history of breast cancer, were not white and had oestrogen receptor negative tumours also had a reduced risk of breast cancer.

The authors said the way in which physical activity protected against breast cancer was likely to be complex and may involve effects on sex hormones, insulin-related factors, the immune system and other hormone and cellular pathways.

Source: British Journal of Sports Medicine 2008; doi:10.1136/bjsm.2006.029132

Exercise Habits Strongly Influenced by Neighborhood

The quality of a neighborhood can encourage—or discourage—people to stay physically active and exercise regularly, says a Chicago study led by Christopher Browning, associate professor of sociology at Ohio State University. Such factors as levels of poverty, lower education, and more families headed up by women can actively discourage exercise habits. The study found that individual income was less important in determining exercise levels as the type of neighborhood involved.

"We can’t encourage people to exercise more without looking at the neighborhood environment in which they live," said says Christopher Browning, co-author of the study and associate professor of sociology at Ohio State University.. "Some people may have the personal resources and desire to exercise, but don’t live in a neighborhood in which they feel comfortable to go outside for activities."

The study found that neighborhood context was more important for women than for men in determining how much they exercised. Additional factors brought out by the study were that levels of trust among neighbors, perceived violence in the community, and beliefs that neighbors help each other, all contributed to how much people exercised in a specific community.

Ming Wen, assistant professor of sociology at the University of Utah, and Kathleen Cagney, associate professor of health studies at the University of Chicago, collaborated with Browning on the study, the results of which appeared in a recent issue of Urban Studies.

The study examined levels of exercise among 8,782 residents of 373 neighborhoods in Chicago, and combined statistics from three data sources from the 1990s: the Metropolitan Chicago Information Center Metro Survey, the 1990 U.S. Census, and the Project on Human Development in Chicago Neighborhoods Survey. Social and economic factors, and the level of poverty were found to be the most important factors affecting levels of physical activity, although neighborhood characteristics were judged to be more important in determining a person’s exercise level than income.

"The result is surprising enough that it needs to be confirmed by other studies," said Browning. "But if the finding is substantiated, it would show just how important neighborhoods are, and would have important implications for any new initiatives aimed at enhancing health and well-being." Women’s exercise habits were affected more by the neighborhood than men, which could also explain why African-American women have much higher obesity rates than other groups, said Browning.

Contrary to other research, this study found that once neighborhood factors were taken into account, African Americans in general exercised as much as white residents did. Browning said this finding suggests African Americans will exercise more if they live in neighborhoods where they feel comfortable doing so.

Source: Ohio State University

TV in Teens’ Bedrooms Promotes Poor Diet and Exercise Routines

University of Minnesota School of Public Health researchers have found that a television in the bedroom promotes poor dietary, study and exercise habits among teenagers. 62% of a sample of 781 teenagers aged 15 to 18 in the Minneapolis area had a television in their bedroom, and spent 4 to 5 hours per week watching television. Bedroom TV owners ranked as heavy watchers, at least 5 hours a day—twice the amount of teenagers without one.

Boys among the television owners achieved a lower grade point average, had less fruit and ate fewer meals with the family than boys without one. Girls owning television sets spent only 1.8 hours per week exercising (versus 2.5 hours for girls without one), consumer less vegetables, ate fewer family meals and drank more sweetened soft drinks.

Daheia Barr-Anderson, one of the research team, was quoted as saying that these results showed that there were clear advantages to banning a TV from a teenager’s bedroom. This view was supported by the American Academy of Pediatrics, which encouraged the removal of TV sets by parents from their childrens’ bedrooms. The findings of the study were published in the Academy’s journal, Pediatrics.

Statistically, the study showed that 68% of boys, compared with 58% of girls, would probably have a bedroom TV, while children from the highest income families were less likely to have one. 82% of black teenagers had a television in their bedroom, while only 66% of Hispanic teens and 60% of whites had one. 39% of Asian American teens reported ownership.

In this study, body mass index was not found to influence teenage obesity, although Barr-Andersen quoted previous studies that showed that ownership of a bedroom TV was a strong predictor of obesity. Both boys and girls with bedroom TV’s admitted to devoting less time to reading and homework, although the differences were not statistically significant, said the researchers.

Sedentary Lifestyle Likely Contributes to Aging, Says Study

People whose leisure time is filled with physical activity appear to be biologically younger than people with a sedentary lifestyles, according to a recent report. “A sedentary lifestyle increases the propensity to aging-related diseases and premature death. Inactivity may diminish life expectancy not only by predisposing to age-related diseases but also because it may influence the aging process itself,” the authors write.

Questionnaires on physical activity level, smoking habits, and socioeconomic status were sent to 2,401 caucasian twins. The twins also gave a blood sample from which DNA was extracted. Also checked were the length of telomeres in the twins’ white blood cells. Telomeres progressively shorten over time and may serve as a measurement of biological age.

People who were less physically active in their leisure time had shorter leukocyte telomeres than those who were more active. “Such a relationship between leukocyte telomere length and physical activity level remained significant after adjustment for body mass index, smoking, socioeconomic status and physical activity at work,” the authors write, “and the most active subjects had telomeres the same length as sedentary individuals up to 10 years younger, on average.”

Sedentary lifestyles can also shorten telomeres by allowing oxidative stress. Physical activity may reduce psychological stress, lessening its effect on telomeres and the aging process.

“The U.S guidelines recommend that that 30 minutes of moderate-intensity physical activity at least five days a week can have significant health benefits’ the authors write. “Our results underscore the vital importance of these guidelines. They also show that adults who partake in regular physical activity are biologically younger than sedentary individuals.”

Source: Arch Intern Med. 2008;168[2]:154-158.

Physical Activity Plus A Mediterranean Diet Can Lower Death Rate Over 5 Years

Eating a Mediterranean diet and following nationally recommended physical activity are associated with a reduced risk of death over 5 years, according to two reports in Archives of Internal Medicine . Data provided by the National Institutes of Health-AARP Diet and Health Study was used in both studies, when 566,407 AARP members aged 50 to 71 returned questionnaires between 1995 and 1996.

A nine-point scale to measure conformity with the Mediterranean diet was used by Panagiota N. Mitrou, Ph.D and colleagues in 380,296 of the participants (214,284 men and 166,012 women) with no history of chronic disease. The diet included vegetables, legumes, fruits, nuts, whole grains, fish, ratio of monounsaturated fats, alcohol and meat. In the 5 years following, 12,105 sample members died, with 5,985 dying of cancer and 3,451 dying of cardiovascular disease. People with higher Mediterranean diet scores were less likely to die of any cause, or of cancer or heart disease.

The second study, supervised by Michael F. Leitzmann, M.D. Dr.P.H., of the National Cancer Institute, analyzed data provided by two questionnaires on physical activity from 252,925 participants (142,828 men and 110,097 women). 7,900 people died. The people who performed physical activity at least 30 minutes most days of the week (the amount of physical activity recommended in national guidelines) were 27% less likely to die. Those who performed vigorous physical activity recommended under the same guidelines (at least 20 minutes three times weekly) were 32% less likely to die. Lesser amounts of physical activity were associated with a 19% reduced risk of death.

Source: Arch Intern Med. 2007;167(22):2461-2468 and 2453-2460.

Healthy Lifestyle More Important than Supplements for Boosting Immune System

A healthy lifestyle—not vitamin and herbal supplemnts—is the most important factor in boosting your immune system, according to a recent report by Harvard Medical School.

While manufacturers of supplements make the claim that suplements "support immunity," there is currently little scientific evidence to support that claim, since scientists have not yet determined what level of immune system cells best helps the body resists disease.

According to the report, The Truth About Your Immune System: What You Need to Know, lifestyle factors that promote overall health are:

  • avoiding smoking
  • eating plenty of fruits, vegetables, and whole grains, and a diet low in saturated fat
  • exercising on a regular basis
  • maintaining a healthy body weight
  • controlling your blood pressure
  • drinking alcohol in moderation, if at all
  • getting enough sleep
  • Avoid infection, for example by frequent hand-washing and safe food preparation habits.

The 43-page report was edited by Dr. Michael N. Starnbach, Ph.D., professor of microbiology and molecular genetics at Harvard Medical School.

Source: Harvard Health Publications

Cheap Running Shoes a Better Buy than Expensive Ones

Why waste money on expensive running shoes when cheaper ones are as good, if not better? That’s the finding of a British research study which compared nine sets of running shoes in three price ranges, bought from three different manufacturers.

Forty three volunteers were used for the study. They were not told the prices, and were asked to rate the shoes for comfort.

Plantar pressure—the force produced by the impact of the sole when hitting the ground—was measured in eight different areas of the sole. It was found to be slightly lower in the cheaper shoes, although the difference between them and the more expensive shoes was not statistically significant. Comfort ratings varied, but again there no obvious difference between the shoes tested.

The authors of the research explained that running produces sizeable shock waves to the bones of the foot, which radiate to other bones in the body. The result is that runners often suffer from knee pain, stress fractures, muscle tears and osteoarthritis.

Running shoe manufacturers claim that the cushioning in more expensive running shoes gives better protection to the sole, and helps prevent these conditions.

Source: British Journal of Sports Medicine 2007; doi: 10.1136/bjsm.2007.038844